ARLINGTON -- Vicente Padilla, on the disabled list with a strained left hamstring, threw in the bullpen without problem on Friday and said he should be ready to start against the Mariners on Tuesday.

"It's feeling good," said Padilla, who is 12-7 with a 4.98 ERA in 25 starts this season.

Padilla has also been bothered by inflammation in a muscle joint between his right shoulder and neck, but that has also improved significantly while he has been on the disabled list. Padilla threw 15 minutes on Friday and will have another bullpen session on Sunday. His last start was on Aug. 24 against the Indians.

"He says he's much better and ready to go," pitching coach Andy Hawkins said. "I don't see any reason why he won't make his next start on Tuesday."

Dustin Nippert has been filling in for Padilla and will remain in the rotation when Padilla returns. The Rangers made that decision after Nippert pitched seven scoreless innings in a 1-0 victory over the Mariners on Wednesday.

"His past couple of starts have made us want to see what it is," Rangers manager Ron Washington said. "It's made us want to take as long of a look as we can. I don't want to anoint anybody, I just want to see what they have to offer."

The Rangers plan to go down the stretch with a rotation of Padilla, Nippert, Kevin Millwood, Brandon McCarthy and Matt Harrison. Scott Feldman, as of now, is only going to get one more start, and that's scheduled for Sept. 14 against the Athletics.

Feldman is in his first year as a starter and the Rangers are concerned about his number of innings. He has pitched a combined 146 1/3 innings this season, including 133 2/3 at the Major League level. He hasn't pitched more than 71 innings in each of the past three seasons.

For now, he'll be used out of the bullpen, and will be again after his one start against the Athletics.